1. Field of the Invention
The present invention relates to liquid crystal displays (LCD), and methods of controlling the LCD to display images.
2. Background of the Related Art
Liquid Crystal Displays (LCDs) have developed significantly and become widely used due to their characteristic light weight, thin shape and low power consumption. Many of today's electronic devices include an LCD, including television screens, computer monitors, notebook computers, and mobile telephones. Some of these devices may even include more than one LCD panel or screen.
LCD screens may incorporate various technologies, but they are based upon a layer of liquid crystals disposed between two transparent electrodes and two polarizing filters. The liquid crystal molecules have a first orientation in the absence of an electric field and are induced into a second orientation upon application of an electric field between the electrodes. The difference in light polarization of the liquid crystals between the first and second orientations is used in combination with the polarizing filters such that control over the electric field determines whether, or to what extent, light will pass through the liquid crystal layer. By arranging large numbers of liquid crystal elements or “pixels” into a two-dimensional array, it is possible to apply the electrical field to selected pixels in order to display images.
However, if any of the pixels are subject to the same electric field over a long period of time, ionic compounds in the liquid crystal layer can build up on one of the electrodes and degrade performance of that particular pixel. Other mechanisms may similarly degrade the LCD pixel such that light transmission through the pixel is affected.